Extraneous heater primarily for motor vehicles operated with liquid fuel, particularly gasoline

ABSTRACT

Heater primarily for motor vehicles operated with liquid fuel particularly gasoline, having a burner, a flame chimney and a heat exchanger, where a vaporizing nozzle is provided as well as a chamber disposed in front of it into which extends at least the electrode of a spark plug and where means are provided for introducing a partial quantity of the air of combustion into the chamber where the spark plug 31 and opposite electrode 32 are so arranged relative to the chamber that their connecting line passes through the center of the fuel cone 36 which extends from the nozzle 27 and bisects the fuel cone 36 in two locations.

[ Mar. 1%, 1972 EXTRANEOUS HEATER PRIMARILY FOR MOTOR VEHICLES OPERATEDWITH LIQUID FUEL, PARTICULARLY GASOLINE Inventors: Eugen Stump,Stuttgart-Unterturkheim;

Gerhard Frankie, Grunbach, both of Germany Firma SuddeutscheKuhleriabrik Julius Fr. Behr, Stuttgart-Feuerbach, Germany Filed: Feb.17, 1970 Appl. No.: 11,980

Assignee:

Foreign Application Priority Data Feb. 18, 1969 Germany ..P 19 07 974.4

References Cited UNITED STATES PATENTS 12/1960 Ryder ..431/264 X2,645,278 7/1953 Holthouse, Sr. et al ..126/110 X 2,757,662 8/1956 Baieret al. ....l26/I1O B 2,881,363 4/1959 DLuzansky ..431/264 X FOREIGNPATENTS OR APPLICATIONS 785,288 10/1957 Great Britain ..126/116 APrimary Examiner-Kenneth W. Sprague AttarneyRobert H. Jacob 15 7]ABSTRACT Heater primarily for motor vehicles operated with liquid fuelparticularly gasoline, having a burner, a flame chimney and a heatexchanger, where a vaporizing nozzle is provided as well as a chamberdisposed in front of it into which extends at least the electrode of aspark plug and where means are provided for introducing a partialquantity of the air of combustion into the chamber where the spark plug31 and opposite electrode 32 are so arranged relative to the chamberthat their connecting line passes through the center of the fuel cone 36which extends from the nozzle 27 and bisects the fuel cone 36 in twolocations.

7 Claims, 3 Drawing Figures Patented March 14, 1972 3,648,681

lnvento r5.- fog-0v JTU/VPA/VO gee/M190 594N415 BACKGROUND OF THEINVENTION The invention relates to liquid fuel heating devices. More inparticular, the invention is concerned with a heater operated withliquid fuel, especially gasoline, having a blower motor and ignitiondevice, primarily an extraneous heater for motor vehicles comprising aburner, a flame chimney and a heat exchanger.

It has been proposed in applicants U.S. Pat. No. 3,543,742 to provide inconnection with a heater of this type, a compression vaporizing nozzleas well as a chamber arranged in front thereof into which extends atleast one electrode of a spark plug and means for supplying a partialquantity of the air of combustion into the chamber.

In known heaters the spark gap is arranged tangentially with respect tothe fuel spray produced by the nozzle. The igniting is achieved by meansof a burning chamber of large dimensions and a flame retainer that isarranged in the gasoline or benzine stream. However, in operation theflame retainer accumulates soot and the spark gap tends to form sootbridges. Known arrangements therefore require a burner chamber of largevolume.

SUMMARY OF THE INVENTION It is, therefore, an object of the presentinvention to deal with the problem of improving a heater in accordancewith applicants earlier patent, particularly with respect to starting atlow ambient temperatures. This object is attained in accordance with theinvention essentially in that the spark plug electrode and the counterelectrode are so arranged relative to the chamber that their connectingline passes through the center of the fuel cone emanating from thenozzle and bisects the fuel cone in two locations.

In accordance with the invention the use of smaller burner chambers ismade possible and the installation of flame retainers is no longerrequired. The arrangement of the ignition electrodes in accordance withthe invention effects that the fuel spray or stream is disturbed in twoplaces so that at these places the supplied air together with the fuelstream results in a correspondingly stoichiometric mixture relationship.

It is a particular advantage if in the housing of the nozzle tubeadditional bores and air supply slots are provided. By blowing a smallamount of nozzle air into the space between the nozzle and the chamberthe spark gap and the end surface are maintained clean also duringcontinuous operation.

In accordance with a further object of the invention a series resistoris connected in series with the blower motor. By means of this seriesresistor the starting speed of the air blower motor is decreased therebyobtaining a relatively rich mixture. After igniting the heater theresistor is cut out by means of a trailing switch known per se.

In accordance with a modified embodiment of the invention the seriesresistor is continually connected with the blower motor and means areprovided for changing the resistance value in relation to thetemperature of the air that is drawn in. It is of particular advantageif for this purpose an adjustable potentiometer is utilized and abimetal device serves as a setting element for this potentiometer.

In accordance with a further development of the invention there resultsan additional improvement of the cold starting characteristics if apressure switch is arranged in the electrical lead to the blower motorwhich is operated by the fuel pressure between the fuel pump and theatomizing nozzle.

BRIEF DESCRIPTION OF THE DRAWINGS Further features and advantages of theinvention will become apparent with reference to the drawing in which anembodiment is schematically illustrated and in which:

FIG. 1 is a cross section through the nozzle and ignition device,

FIG. 2 is a view taken along the line of arrow A in FIG. I, and

FIG. 3 is a circuit diagram of the electrical connections.

DESCRIPTION OF THE INVENTION In accordance with FIG. 1 a spark plugmounting 24 is provided on the housing portion 22 of the heater intowhich a spark plug 25 is inserted. A projecting member 26 is connectedwith the housing 22 in which a pressure nozzle 27 is disposed. In frontof the nozzle 27 a chamber 30 is provided into which the spark plug 25projects at least with its ignition electrode 31. Furthermore, a counterelectrode 32 is provided. Between the ignition electrode and the counterelectrode the ignition spark jumps over in a known manner when theignition is turned on. The ignition electrode 31 and the counterelectrode 32 are so arranged that their connecting line bisects the coneof fuel in two locations and heats the central axis of the fuel cone 36.

The spark plug mounting 24 has apertures 33 and is designed in such amanner that around the ignition electrode 31 a circular space having anaperture 34 is formed. Between the chamber 30 and the spray nozzle 27 aheat shield plate 35 is provided.

Furthermore, generally annular twist plates 38 having inclined guideblades 39 are provided. These twist plates take care of intimate mixingof the air of combustion with the atomized fuel drawn in and supplied bythe combustion air blower.

Furthermore, a bore with an auxiliary air slot 40 is provided in thehousing 22. Several such bores or additional air supply slots may beprovided. Through these additional air supply slots 40 flows nozzle airthat makes possible the cleaning of the nozzle front surface and of thespark gap during operation.

In FIG. 2 which shows a view of the device in accordance with FIG. I inthe direction of the arrow A corresponding parts are identified by thesame reference numerals.

The circuit means for operating the heater in accordance with theinvention are shown in FIG. 3. A vehicle connected fuse 41 is provided.The device can be turned on manually by means ofa switch 42. It ispossible, however, to construct the switch 42 as a contact of a timeswitch relay (not shown). The switch 42 closes the circuit to the blowermotor 11. A control lamp 45 is connected parallel thereto. A temperaturetrailing related switch 46 is arranged in the circuit of the motor.After turning off the heater the blower continues to run.

In accordance with the invention a series resistor 56 is connected inthe circuit with the blower motor 11. The arrangement in this connectionmay be such that the series resistor 56 is turned off by the trailingswitch 46 after ignition. The switch 42 opens or closes the contact tothe fuel pump 47 as well as that of an ignition coil 48. The ignition iseffected by way of a capacitor 49 in which connection a contact 50serves as the ignition interrupter which simultaneously andadvantageously may be mounted at the fuel pump. Furthermore, a safetythermostat 51 is provided as well as a control thermostat 52 whichserves for maintaining a certain fuel temperature that may bepreselected.

The apparatus is turned on by means of the switch 42 which causes thepermanent ignition, the fuel pump and the blower motor to start. At thesame time the control lamp 45 indicates the condition of operation. As aresult of heating the trailing switch 46 the contacts thereof close sothat as the switch 42 is opened subsequent aerating of the burnerchamber takes place. Only after the aerating has been terminated thecontrol lamp 45 becomes extinguished. The overheating thermostat 51stops the fuel pump 47 and the ignition in the event of excessivetemperature. This thermostat has to be set back manually after it hasresponded.

In accordance with a further feature of the invention the seriesresistor 56 that is in the form of a potentiometer is equipped with apickup arm 57. The arm 57 is suitably displaced or moved by atemperature dependent device, for example, a bimetal strip 58. Thesetting takes place in relation to or as determined by the temperatureof the air drawn in.

In accordance with a further development of the invention a pressureswitch 59 is provided in the lead to the blower motor 11. This pressureswitch 59 is actuated by the fuel pressure in the fuel conduit betweenthe fuel pump 47 and the spray nozzle 27. As a result. when the fuelpressure is below an adjustable value the current supply to the blowermotor 11 remains interrupted. Thus the blower driven by the electromotor11 does not supply air of combustion.

The small quantity of fuel sprayed in as a result of the small fuelpressure can nevertheless ignite because air of combustion is present inthe burner space. Due to the existing flame the burner chamber 30 andthe spray nozzle 27, as well as the fuel supply conduit heat up so thatthe fuel becomes thin-flowing and a higher pressure can slowly build upin the fuel supply conduit.

If this pressure rises above a predetermined value, the pressure switch59 is actuated and the current supply to the electromotor 11 isreleased. The blower now starts and supplies additional air ofcombustion into the burner chamber 30. Inasmuch as the burner chamber 30is now heated by a predetermined amount, the flame can no longer beblown out by the cold air ofcombustion such as is the case if the blowerstarts together with the fuel pump 47.

The invention is not limited to the embodiment illustrated and describedbut it encompasses also all advantageous modifications familiar to theman skilled in the art and particularly all partial and subcombinationsof the features described and/or illustrated. The components of theheater not described above are explained in detail in the US. Pat. No.3,543,742.

Having now described our invention with reference to the embodimentsillustrated in the drawings, what we desire to protect by letters patentis set forth in the appended claims.

We claim:

1. In a liquid fuel heater for motor vehicles or the like primarilyoperated with gasoline, comprising a housing defining a heat exchanger,a flame chimney in said heat exchanger, a burner proximate said heatexchanger, a pressure fuel spraying nozzle in aspirating relation tosaid burner adapted to spray a fuel cone into said burner, a burnerchamber adjacent said fuel nozzle in said flame chimney, a fuel pump anda fuel supply conduit connected to said fuel nozzle for supplying liquidfuel to said nozzle, a blower motor for supplying air of combustion,means proximate said fuel nozzle for admitting a partial quantity of airof combustion into said chamber, ignition means including a spark plughaving an electrode extending into said chamber and a counter electrodein said chamber on the side opposite said spark plug electrode, anelectric circuit connected to said blower motor and to said spark plugfor supplying current thereto, said spark plug electrode and saidcounter electrode being disposed along a connecting line passing throughthe centerline of the fuel cone emanating from said nozzle and bisectingsaid fuel cone in two locations.

2. The improvement in a heater in accordance with claim 1, comprising ahousing portion extending around said nozzle, and having at least oneair aperture proximate and radially of said nozzle.

3. The improvement in a heater in accordance with claim 1, where saidblower motor is connected in said electric circuit and a resistor isconnected in series with said blower motor.

4. The improvement in a heater in accordance with claim 3, including atrailing switch in said circuit of said resistor operative to disconnectsaid resistor.

5. The improvement in a heater in accordance with claim 3, where saidresistor is continuously connected in series with said blower motor andmeans are provided for changing the value of said resistor in relationto the temperature of the air drawn in by said blower motor.

6. The improvement in a heater in accordance with claim 5, where saidresistor is a potentiometer and said means for changing the resistancevalue of said resistor include a sliding contact in the form ofa pickuparm and a bimetal strip.

7. The improvement in accordance with claim 1 including a pressureswitch in the circuit of said blower motor responsive to the fuelpressure in said fuel conduit between said fuel pump and said fuelspraying nozzle.

1. In a liquid fuel heater for motor vehicles or the like primarilyoperated with gasoline, comprising a housing defining a heat exchanger,a flame chimney in said heat exchanger, a burner proximate said heatexchanger, a pressure fuel spraying nozzle in aspirating relation tosaid burner adapted to spray a fuel cone into said burner, a burnerchamber adjacent said fuel nozzle in said flame chimney, a fuel pump anda fuel supply conduit connected to said fuel nozzle for supplying liquidfuel to said nozzle, a blower motor for supplying air of combustion,means proximate said fuel nozzle for admitting a partial quantity of airof combustion into said chamber, ignition means including a spark plughaving an electrode extending into said chamber and a counter electrodein said chamber on the sidE opposite said spark plug electrode, anelectric circuit connected to said blower motor and to said spark plugfor supplying current thereto, said spark plug electrode and saidcounter electrode being disposed along a connecting line passing throughthe centerline of the fuel cone emanating from said nozzle and bisectingsaid fuel cone in two locations.
 2. The improvement in a heater inaccordance with claim 1, comprising a housing portion extending aroundsaid nozzle, and having at least one air aperture proximate and radiallyof said nozzle.
 3. The improvement in a heater in accordance with claim1, where said blower motor is connected in said electric circuit and aresistor is connected in series with said blower motor.
 4. Theimprovement in a heater in accordance with claim 3, including a trailingswitch in said circuit of said resistor operative to disconnect saidresistor.
 5. The improvement in a heater in accordance with claim 3,where said resistor is continuously connected in series with said blowermotor and means are provided for changing the value of said resistor inrelation to the temperature of the air drawn in by said blower motor. 6.The improvement in a heater in accordance with claim 5, where saidresistor is a potentiometer and said means for changing the resistancevalue of said resistor include a sliding contact in the form of a pickuparm and a bimetal strip.
 7. The improvement in accordance with claim 1including a pressure switch in the circuit of said blower motorresponsive to the fuel pressure in said fuel conduit between said fuelpump and said fuel spraying nozzle.